FIAT, FIANT 



262 



FIBRIN 



on the intervening day. F., Tropical, yellow fever. 

 F., Typhotyphus, Pepper's name for mild typhus 

 marked by laxity of the bowels, tympanites, epistaxis, 

 and bronchial disturbance, the eruption occurring on the 

 fourth day and the crisis from the tenth to the four- 

 teenth day. F., Undulant [Hughes]. Synonym of 

 Mediterranean fever. F., Uniform, simple con- 

 tinued fever. F., Urban, a fever enduring about 3 

 weeks and similar to mild typhoid except that specific 

 symptoms are absent. F., Uremic, one due to poison- 

 ing from urinary ptomains ; it has been observed after 

 operations on the urinary tract or in urinary diseases. 

 F., Urethral, one due to operation on the urethra ; it 

 may be due to septic infection. F., Walking Ty- 

 phoid. See Ambulatory Typhoid (Illus. Diet. ). F., 

 Water-brain. See F\, Brain-water. F., White, 

 a slight fever attending chlorosis, to which it was 

 thought to be due. F., Winter, pneumonia. F., 

 Wound. See F., Traumatic (Illus. Diet.). 



Fiat, Fiant (fi'-at, fi'-ant) [pres. subj., third person, 

 sing, and pi. of fieri, to be made]. Let there be 

 made. 



Fiber. (See Illus. Diet.) F.s, Accelerating, nerve- 

 fibers which convey impulses that hasten the rapidity 

 and increase the force of the heart-beat. Syn., F, 

 Augmentor ; F., Augmented; Nervi accelerantes 

 cordis. F., Achromatic. See Karyomitoma (Illus. 

 Diet.). F.s, Annular, those forming a circle around 

 an organ or part. F.s, Arciform, F.s, Arcuate, 

 transveise curving fibers intersecting the longitudinal 

 fibers of the reticular formation ; they are divided into 

 deep and superficial sets. The first spring mainly 

 from the decussation of the pyramids and the raphe 

 and bend outward and backward ; one part passes 

 to the nucleus gracilis and the cuneate nucleus and one 

 part (internal arciform fibers) through the olivary 

 nucleus and thence into the restis. The superficial 

 arciform fibers spring from the same source and pro- 

 ceed to the restis ; one part (external arciform fibers, 

 Rolando's arciform fibers) passing outward at the ante- 

 rior median fissure runs outward on the pyramid and 

 olive and the other part passes out laterally behind 

 the pyramid. F.s, Association, white nerve-fibers 

 situated just beneath the cortical substance and con- 

 necting the adjacent cerebral gyri. F.s, Augmented, 

 F.s, Augmentor. See F.s, Accelerating. F.s, 

 Auxiliary. See F.s, Secondary. F., Axial. (See 

 Illus. Diet.) 2. The central spiral filament, probably 

 contractile, of the flagellum of the semen-cell. F.s, 

 Bergmann's, F.s, B.-Deiters', the processes of cer- 

 tain superficial neuroglia cells of the cerebellum which 

 radiate toward the surface and are connected with the 

 pia mater. F.s, Bernheimer's, a tract of nerve -fibers 

 extending from the optic tract to Luys' body. F.s, 

 Bogrow's, a tract of nerve-fibers passing from the optic 

 tract to the thalamus. F.s, Charcot's. See Radicular 

 Fasciculus, Internal ; and A'. Fibers, External (Illus. 

 Diet.). F.s, Collateral, the delicate lateral brandies 

 of the nerve-process of a neuron. The paraxons. F.- 

 cone. See under" Cone. F., Darkschewitsch's, a 

 tract of nerve-fibers extending from the optic tract to 

 the ganglion of the habenula. F.s, Dartoic, the 

 muscle-fibers of the dattos. F., Elastic. See under 

 Tissue, Yellow Elastic (IHm. Diet.). F.s, Henle's. 

 See under Henle (Illus. Diet.). F.s, Herxheimer's. 

 See Spirals, Herxheimer's (Illus. Diet.). F.s, In- 

 voluntary Muscular, straight or slightly bent, elon- 

 gated, spindle-shaped, nucleated cells bearing more 

 or less distinct longitudinal striations, which make 

 up involuntary or unstriped muscles. Syn., F.s, 

 Nonsttiated ; F.s, Unstriped; F.s, Unstriated. See 

 Muscular Tissue (Illus. Diet.). F.s, Meynert's, 



a tract of nerve-fibers connecting the pregeniculum 

 with the nuclei of the ocular muscles. F.s, v. Mon- 

 akow's, a tract of nerve-fib rs extending fiom the 

 pregeniculum to the eyeball. F.s, Moss. See Moss- 

 f.s. F.s of Mummery, scaffolding in which the gela- 

 tinous tissue and calcospherites are deposited in dental 

 pulp. F., Muscle-, F., Muscular, any elongated 

 anatomic element made up of muscular constituents. 

 F., Nerve-. See under Nerve (Illus. Diet.). F.s, 

 Osteogenic. See F.s, Sharpens Intercrossing. F.s, 

 Prussak's. See under Frussak (Illus. Diet. ). F.s, 

 Purkinje's. See under Purkinje (Illus. Diet.). F.s, 

 Radicular, Internal. See Radicular Fasciculus, 

 Internal (Illus. Diet.). F.s, Retzius', the rigid fila- 

 ments of Deiters' cells in the organ of Corti. F., 

 Ritter's, a delicate fiber, regarded as a nerve-fiber, seen 

 in the axis of a retinal rod near the peripteral end of 

 which it forms a small enlargement. F.s, Rivet-, 

 protoplasmic processes on the basal surface of the colum- 

 nar cells of stratified squamous epithelium; German, 

 Haftfasern. F.s, Rolando's Arciform. See Rolando 

 (Illus. Diet.). F.s, Sappey's, smooth muscular fibers 

 found in the check ligaments of the eyeball close to their 

 orbital attachment. F.s, Secondary, in a fibrous struc- 

 ture, those of secondary importance. Syn., Auxiliary 

 fibers. F.s, Sharpey's Intercrossing, the collagenous 

 fibers forming the lamellas which constitute the walls of 

 the Haversian canals in bone ; same as osteogenic fibers. 

 F.s, S.'s Perforating, calcified white or elastic fibers 

 which connect the lamellas in the walls of the Haver- 

 sian canals. F. -sheath. See Sheath, Fibril (Illus. 

 Diet.). F., Smooth Muscular, a muscular fiber-cell. 

 See under Muscle, Unstriped or Involuntary (Illus. 

 Diet). F.s, Spindle, achromatic fibrils. F., Spiral, 

 the coiled fiber peculiar to spiral fiber-cells (</. v., under 

 Cell). F.s, Stilling's, the association fibers of the 

 cerebellum. F., Straight, the uncoiled fiber, in a 

 bipolar ganglion cell. See under Cell, Spiral-fiber. 

 F.s, Striated or Striped Muscular. See F.s, 

 Voluntary Muscular. F., Sweat, a nervous fibril 

 which on stimulation produces sweating. F.s, Sym- 

 pathetic, those of the sympathetic nerve. F., T, a 

 branch given off at right angles to the axis-cylinder of 

 a nerve-cell. F., Unstriated Muscular, F., Un- 

 striped Muscular. See /"., .Involuntary Muscu- 

 lar. F.s, Vascular. See under Vascular (Illus. 

 Diet.). F.s, Vasodilator, fibers of a vasodilator 

 nerve. F., Voluntary Muscular, narrow, cylindric, 

 fusiform columns marked by regular transverse stripes, 

 which compose voluntary or striped muscles. See 

 Muscular Tissue (Illus. Diet. ). F.S.Wernicke's. 

 See Radiation, Optic (Illus. Diet.). F.s, White. 

 See under Tissue, White Fibrous (Illus. Diet.). F.s, 

 Yellow Elastic. See under 7'issue, Yellow t 

 (Illus. Diet). 



Fibriform (fib'-ri-form) \_fibra, fiber ; forma, shape]. 

 Shaped like a fiber. 



Fibril. (See Illus. Diet) 3. The subdivision of a 

 muscular fiber. F., Achromatic. See Karyomita 

 (Illus. Diet). F.s, Ebner's Dentinal, delicate 

 fibrils contained in the matrix of the dentin. F., 

 Nuchar. See Threads, Nuclear. F.s, Remak's, 

 the fibrils composing a nonmedullated nerve-fiber. 



Fibrillation. (See Illus. Diet) 2. Huxley's name 

 for the propensity of periplastic substance to break up 

 into definite lines. F., Muscular. See Fibronivitit 

 (Illus. Diet). 



Fibrin. (See Illus. Diet) Syn., Materia fibrosa; 

 Coagn table lymph. F., Canalized, a hyaline, pecu- 

 liarly lustrous substance permeated by numerous chan- 

 nels, found in the region of the chorion frondosum at 

 four months and after; which, according to Minot, 



